Solved
Ok, so i have a problem.
I need to model a use case diagram for a new CMS system. the point is, there is a "superAdmin" who can do all the same stuff as the client (buyer of the website) and more.
When I model this my Use case diagram turns into a spider web. And i'm guessing that isn't good.
Would there be any other good way to model this?
Model: ...
What could I do to make model this right?
And yes, almost everything is "Manage (beheer in dutch)". That is because a client want to CRUD almost everything of his website.
Solution
Generalization between actors.
For more information I suggest reading:
Microsoft
Modern Analyst
See also:
uml-diagrams.org: Relationships Between Actors
Related
I am currently implementing an app and I am on the design stages at the moment. I know for a fact that the deployment diagram is fairly easy to model and can be done in the space of 2 hours.
Likewise, what are some of the easiest UML diagrams to model - i.e ones that don't require much effort and time. I am asking as I have a tight schedule in terms of other commitments and I want to get all the same bits and bobs out of the way
Also, what is the difference between a localhost server - i.e one on your laptop, and a normal remote server? I just need to know so that I can model my deployment diagram.
Thanks
Sorry, but that question is complete nonsense. You never model a diagram. You model a model and show it to humans by means of diagrams. So to answer your question: The easiest one is one that shows nothing at all (take any possible diagram you like). That way you also show nothing. If you want to show something, you need to take the effort to compose the diagram(s).
Maybe you think over your question.
P.S. Have you ever had a homework at school to describe a picture? It's analogous: if you just say "it's paint inside a rectangle frame" then it's a description. But a poor one. You can go on an say "There's a face of a person" (if it's a portrait). That would say a bit more, but you see that the essence is hard to find. IIRC Euklid has been asked if there's a king's way to mathematics. You probably know his answer.
Sorry Cons.
The answer of course is none as that is the quickest. However this is feeling like a class assignment so i will guess that you should probably do a class diagram and a deployment diagram.
Often if you have to describe the chat between two objects between two machines, lots of other diagram types come in. I like activity diagrams with swimlanes for that.
I generally use a use case diagram, with one activity diagram per use case. I also use a class diagram. Those are probably the fundamentally necessary diagrams. I only use a deployment diagram if the deployment is fairly complex.
The reason that you're getting some negative feedback is that you appear to be asking how to make a good impression rather than how to do the job right. If your priority is to do diagrams with a minimum of effort rather than to create useful diagrams, the easiest thing is not to do them at all. Otherwise, use diagrams to explain the model in the simplest way possible.
There are some Topics on Stackoverflow already related on how to model different Threads in UML, for example: Is there an inituitive UML approach to depict threads.
However I still feel, that my case has not been already discussed, even though it should be pretty common:
I am creating an iPhone Application, where I am obviously have a Main-UI-Thread and I am also using Background-Threads to perform Remote-Calls, etc. I basically have 4 different aspects that I like to display within my diagramm:
The UI that is shown to the User.
The Tasks that are being performed by the Main-UI-Thread (therefore blocking the UI)
The Tasks that are performed by Background-Threads
Updates of the UI, which are performed by the UI-Thread, but can be triggered by Background-Threads. For example: new Information loaded from Server, which needs to be displayed on the UI
Has anybody ran into a similiar issue and therefore might show me an example or give me some best practises on how to solve my problem? I am not even sure if I should use a sequence-diagram, an activity-diagram or maybe even some other type.
Well Pascal,
This is not an UML question. It is a design question.
UML just helps you
To understand hard and crtical section of your program/design and to
explore alternative solutions , while writing your code. with the power of visual modeling.
So..
First, ask yourself what kind of parallelism or concurrency exist in
your problem? To investigate this:
Draw a simple activity diagram with partions in which each partions
used to represent different operating system threads or processes.The
object nodes can be used to model the shared objects and data.Forking can be used to model the creation and parallel execution of multiple threads or processes.
Then ask yourself(using that diagram)
What are my shared data? What are my active classes? (threads)What kind of "concurency" problems" may
accour? What may go wrong? What are synronization points? etc..Based on this Explore different alternatives, designs.
The last thing you should worry is UML and its sytax(symbols).
The best UML diagrams are the one that wake up the desire of "asking question" in your mind.
At first forget about Uml. Ask core questions about your problem. If you like visual modeling and your mind like visual thinking use Uml for better understand and investigate possible design solutions.
UML can not design for you...
I found this research papers while searching for same thing
M-UML: an extension to UML for the modeling of mobile
agent-based software systems
May be it can help you
I am learning MVVM now and I understand few things (more than but few are here..):
Does every model potentially exposed (thru a VM) to the View is having a VM?
For example, if I have a Contact and Address entity and each contact has an Addresses (many) property, does it mean I have to create a ContactViewModel and an AddressViewModel etc.?
Do I have to redeclare all the properties of the Model again in the ViewModel (i.e. FirstName, LastName blah blah)? why not have a ViewModelBase and the ContactViewMode will be a subclass of ViewModelBase accessing the Entity's properties itself? and if this is a bad idea that the View has access to the entity (please explain why), then why not have the ViewModelBase be a DynamicObject (view the Dictionary example # the link page), so I don't have to redeclare all the properties and validation over and over in the two tiers (M & VM) - because really, the View is anyway accessing the ViewModel's fields via reflection anyway.
I think MVVM was the hardest technology I've ever learned. it doesn't have out-the-box support and there are to many frameworks and methods to achieve it, and in the other hand there is no arranged way to learn it (as MVC for instance), learning MVVM means browsing and surfing around trying to figure out what's better. Bottom line, what I mean by this section is please go and vote to MSFT to add MVVM support in the BCL and generators for VMs and Vs according to the Ms.
Thanks
What a telepathy!
I enjoyed so much reading this great article of Robert McCarter's, he talked just about what I felt painful with! especially about the proxy-properties (now I even know it's name...).
I would warmly recommend this article to every MVVM confusee (like me - I am sure there are a lot!)
1/2) Like with most programming problems... It all depends.
It depends upon how you've linked together the ideas. You can re-expose the needed model properties in the view model if it fits your needs. Hide model proporties that you don't want the user to interact with like a DB key. You can put the model validation logic in the model or the view model. It all depends on what works for you and your situation, which is why it is hard to directly answer the question.
I am using the ViewModelBase for functionality shared by ALL of the ViewModels. I've been using the base object to handle INotifyPropertyChanged code and little else.
3) Take a look at Karl Shifflett’s web site. Karl has a bunch of code you can look at. Stuff and BBQ Shack are working MVVM projects. He also has a complete MVVM training module here.
I'd post some links, but I'm limited to 2 links per post.
I have finally decided to hop up on the train of MVC 2.
Now I have been doing a lot of reading lately and following is the architecture which I think will be good enough for most Business Web Applications.
Layered Architecture:-
Model (layer which communicates with Database). EF4
Repository (Layer which communicates with Model and includes all the queries)
Business Layer (Validations, Helper Functions, Calls to repository)
Controllers (Controls the flow of the application and is responsible for providing data to the view from the Business Layer.)
Views (UI)
Now I have decided to create a separate project for each layer (Just to respect the separation of concerns dilemma. Although I know it's not necessary but I think it makes the project look more professional :-)
I am using AutoMetaData t4 template for Validation. I also came across FluentValidation but cant find much on it. Which one should I go with?
Which View Engine to go for?
Razor View Engine Was Love at first sight. But it's still in beta and I think it won't be easy to find examples of it. Am I right?
Spark .. I can't find much on it either and don't want to get stuck somewhere in the middle crying for help when there is no one to listen...:-(
T4 templates auto generate views and I can customize them to generate the views the way I want? Will this be possible with razor and spark or do I have to create them manually?
Is there any way to Auto generate the repositories?
I would really appreciate it if I can see a project based on the architecture above.
Kindly to let me know if it's a good architecture to follow.
I have some confusion on the business layer like is it really necessary?
This is a very broad question. I decided to use Fluent NHibernate's autoconfig feature for a greenfield application, and was quite impressed. A lot of my colleagues use CakePHP, and it needed very little configuration to get it to generate a database schema compatible with the default conventions cake uses, which is great for us.
I highly suggest the book ASP.NET MVC2 in Action. This book does a good job at covering the ecosystem of libraries that are used in making a maintainable ASP.NET MVC application.
As for the choice of view engines, that can depend on your background. I personally prefer my view to look as much like the HTML as possible, so I would choose Spark. On the other hand if you are used to working with ASP.NET classic, the WebForms view engine may get you up and running fastest.
Kindly to let me know if its a good architecture to follow?
It's a fine start - the only thing I would suggest you add is a layer of abstraction between your Business Logic and Data Access (i.e: Dependency Inversion / Injection) - see this: An Introduction to Dependency Inversion.
i know its not necessary but i think it makes the project looks more professional :-)
Ha! Usually you'll find that a lot of "stuff" isn't necessary - right up until the moment when it is, at which point it's usually too late.
Re View Engines: I'm still a newbie to ASP.NET MVC myself and so aren't familiar with the view engines your talking about; if I were you I'd dream up some test scenarios and then try tackling them with each product so you can directly compare them. Often, you need to take things for a test drive to be more comfortable - although this might take time, but it's usually worth it.
Edit:
If i suggest this layer to my PM and give him the above two reasons then i don't think he will accept it
Firstly, PM's are not tech leads (usually); you have responsibility for the design of the solution - not the PM. This isn't uncommon, in my experience most of the time the PM isn't even aware they are encroaching on your turf that isn't theres. It's not that I'm a "political land grabber" but I just tend to think of "separation of concerns" and, well, I'm sure you understand.
As the designer / architect it's up to you to interpret requirements and (taking business priorities into account) come up with solution that provides the best 'platform' going forward.
(Regarding DI) My question is , is it really worth it?
If you put a gun to my head I would say yes, however the real world is a little more complex.
If you answer yes to any of these questions then its more likely using DI would be a good idea:
The system is non-trivial
The expected life of the system is more than (not sure what the right figure is here, there probably isn't one, so I'm going to put a stake in the ground at) 2 years.
The system and/or its requirements are fluid.
Splitting up the work (BL / DAL) into different teams would be advantageous to the project (perhaps you're part of a distributed team).
The system is intended for a market with a diverse technical landscape (e.g: not everyone will want to use MS SQL).
You want to perform quality testing (this would make it easier).
The system is large / complex, so splitting up functionality and putting it into other systems is a possibility.
You want to offer more than one way to store data (say a file based repository for free, and a database driven repository for a fee).
Business drivers / environment are volatile - what if they came to you and said "this is excellent but now we want to offer a cloud-based version, can you put it on Azure?"
Id also like to point out that whilst there's definitely a learning curve involved it's not that huge, and once you're up-to-speed you'll still be at least as fast as you are now; or at worst you;ll take a little longer but you'll be providing much more value (with relatively less effort).
In terms of how much effort is involved...
One-Off Tasks (beyond getting the team up to speed):
Writting a Provider Loader or picking DI Framework. Once you've done this it will be reusable in all your projects.
'New' Common Tasks (assuming you're following the approach taken in the article):
Defining interface (on paper) - this is something you'll be doing right now anyway, except that you might not realise it. Basically it's OO Design, but as it's going to be the formal interface between two or more packages you need to give it some thought (and yes you can still refactor it - but ideally the interface should be "stable" and not change a lot; if it does change it's better to 'add' than to 'remove or change' existing members).
Writting interface code. This is very fast (minutes not hours), as you're not writting any implementation; and when you go to implement you can use tools provided by your IDE to generate code-stubs based on the interface.
Things you do now that you'd do differently:
Instantiating a variable (in your BL classes) to hold the provider, probably via a factory. Writting this shouldn't take long (again, minutes not hours) and it's fairly simple code to copy, paste & refactor where required.
Writing the DAL code: should be the same as before.
Sometimes it is way more easy to learn patterns from code : Sharp Architecture is a concrete implementation of good practices in MVC, using DDD.
What is CSLA Framework and Its use ?
My Opinions From My Experience w/ a 1.7M LOC code base:
CSLA is intended for a distributed application/database environment. This is why the basic business object is and does everything, for example it's own data persistence. An object (and everything remotely associated w/ its state) is intended to be serialized, sent to a different application and/or data server and work.
If the above is not a problem you need to solve, CSLA is overkill, big time. Our development team regrets having committed to CSLA.
Juggling all the CSLA balls in a complex Windowed UI is tough. We have multi-tabbed screens (which may in turn open sub-screens) that, unless you follow the "left to right, top to bottom" flow of data entry, and click save often, ends up putting and/or fetching incomplete data to/from the database; or dropping data altogether that you just entered. Yes, our original coders are at fault, but so is CSLA... It just seems that there are so many moving parts to enable, control, and coordinate CSLA features. It's like having to deal with all the dials & switches of a fighter jet when all you really need is something more like a Cessna 152.
You will write lots of custom code to enable the CSLA features. For example CSLA will never be confused with object relational mapper (ORM) tools like Hibernate and Entity Framework. Our SAVE() methods are non trivial, so are the trivial ones.
Encouraging the use of code generators compounds problems. We used CodeSMith to generate classes from data tables. So we end up with code that has a 1-1 correspondence of table to c# class. So you must write all the code to handle dataStore to your "real" objects.
Data store/ and fetch is very inefficient w/ CSLA. Because of the Behemoth, monolithic BusinessObject-does-all-and-knows-all centric paradigm, objects end up doing a one-object-at-a-time data fetch and instantiate. Collections of composite objects significantly compound the problem. A single "get this object" always results in a cascade of separate data fetches (one or more for each individual object) to instantiate the entire inheritance & composite relationship chains. Its known as the "N+1 query problem." Oh, and fetching data ALWAYS results in a new object being created, even if we're only updating an existing one. No wonder our more complex screens are FUBAR.
It allows you to architect your application with solid object oriented principals and a good seperation of concerns.
Yes and no. Mostly no.
The BusinessObject handles it's own data storing. That is anti separation of concerns.
"It allows you..." well, yeah - so does a blank text editor screen, but does not force or encourage you like the MVC.NET framework does, for example. IMHO, CLSA provides absolutely zero benefit for ensuring that the code you develop with it follows "solid OO principles". In fact coders w/ weak OO skills (the majority, in my experience) will really stand out when using CSLA! Woe betide the maintenance programmer.
CSLA is the poster child for the solid object oriented principle favor composition over inheritance. CLSA code is untestable. Because an inherited framework BusinessObject is, does, and needs everything, all at once and every time, it's not likely that you will be able to get much test coverage. You can't get at the pieces because everything is tightly coupled.The framework is not amenable to dependency injection. It is an iron curtain of code.
Your code will be difficult to debug. Call stacks get very deep and as you get near the center of the sun so to speak, everything turns into reflection - "what *&^# methods just got called???" And you simply get lost. period.
EDIT 7 Mar 2016
What more insight can I add after the original post? Two things, perhaps:
First, It feels like CSLA has some promise. If we knew how to juggle all those moving parts together. But CSLA is so enigmatic that even things we have done right are corrupted over time. IMHO without a very strong team-wide CSLA wherewithal, any implementation is doomed. Without a vibrant "open source" of technical references, training, and community it's hopeless. In almost a decade our CSLA code, in my final analysis, is just compounding technical debt.
Second, here is a recent comment I made, below:
Our complexity often does not seem to fit in the CSLA infrastructure
so we write outside of the framework. This and cheap labor results in
rampant SRP violations and has me hitting brick walls managing dynamic
rule application, for example. Then, CSLA parent/child infrastructure
propagates composite object validation but we don't always want c/p
relationships, so we write more validation and store code. So today
our CSLA implementation is inconsistent & confusing. Refactoring to
more-better CSLA will have profound domino effects. So after that
initial injection CSLA is essentially abandoned.
end Edit
CSLA is business object framework that allows you to easily create business objects on top of a data layer. It allows you to architect your application with solid object oriented principals and a good seperation of concerns.
I would highly recommend you read the CSLA book by Rocky Lhotka called Expert C# 2008 Business Objects. That will not only teach you about the framework but also teach good software architecture principals.
You can grab the book here on Amazon
I suggest reading the What is CSLA? page, and browse through the CSLA .NET FAQ site.
For the latest published information check out the Using CSLA 4 ebook series.
In reply to #radarbob https://stackoverflow.com/a/10922373/261363, hope I won't regret this and start a flame war.
Our team has been developing a couple of LOB applications with CSLA. From my experience on writing green field apps with CSLA and maintaining existing code here are my replies to your points.
The BO is not suppose to do it's own data persistence, you will have a Factory that will handle all data persistance, for example using a ORM to map to Models that are later on saved.
Sorry to hear that, I make sure I study the framework documentation and write at least one toy application before committing to a existing code database. Furthermore you can even download and browse the CSLA code.
You have BO -> Portal -> Factories that should not be very complicated the existing CSLA examples go a long way on explaining what is happening on each level.
CLSA should never be confused with a ORM
As you should, business object are rarely mapped to one table and thus require a bit of work when saving. In the case they are mapped to one table to you use something like AutoMapper to map your BO to your POCO in 1 line.
Look into CSLA Commands, also is nothing stopping you from keeping your BO as small or big as you want as long as you keep in mind that they are not the same as the POCO's that you will persist.
In a project we worked on we where able to easily test BO to ensure that the business logic was correct. Because of the nice separation of concerns we tested our Factories in isolation to make sure that business objects will be persisted accordingly.
At one point I was able to easily persist part of my BO's in MongoDB so the application was running on a hybrid database MSSQL and MongoDB without having to even change one line of code in my business objects, all I had to do was to update the factories to use Mongo instead of the current ORM.
Hope this addresses all your points in a fair manner,
Regards
CSLA: Component-based Scalable Logical Architecture
A paragraph in a nutshell that described CSLA to me from the website was this:
CSLA .NET enables you to create an object-oriented business layer that abstracts and encapsulates your business logic and data. The framework ensures your business objects work seamlessly with all .NET interface technologies, including WinRT XAML, WPF, ASP.NET MVC, ASP.NET Web Forms, WCF, asmx services, Windows Phone 7, Silverlight, Windows Workflow and Windows Forms.
Why you might use it:
Business rule management. Once you learn the business rule system, it provides a way to enforce business logic in a tidy package. If you have an object with child objects that need to report Validation to the parent most level, there is a way to handle that. (see http://www.lhotka.net/weblog/CSLA4BusinessRulesSubsystem.aspx for more information on the rule system)
You have business objects that you need to support N-level undo? A CSLA BusinessBase has a baked in property management system (like dependency properties) for functionality like N-Level Undo (it is actually completely implemented.) (This also ties into the business rule management. You can fire validation when a primary property changes, or you can change a property based on the value of another property.)
Data portal management. This one was an interesting concept. If I need to execute data operations locally, CSLA is configured for this out of the box. I can also stand up a WCF service that references my business object libraries, and use a few lines of configuration to make a WCF endpoint to manage data operations. The WCF service is a part of the CSLA framework. It was neat to see this in action. Other scenarios? Sure! Your business object library doesn't need to change, the DataPortal class determines if it needs to execute remotely or locally, according to your configuration.
CSLA does force you to use a few mechanisms that may not feel natural at first. I think that is somewhat true of any pattern you choose to implement. However, when it comes to the challenges of implementing Service Oriented Architecture, CSLA offers a lot. Yes, you are going to have an architect level developer authoring some of your libraries. However, if you're building an enterprise class application, shouldn't you be doing that already?
CSLA, when architected correctly, is testable. We use the repository pattern to replace out the actual dal with a mock layer and test both by specification (using NUnit/SpecFlow) and in a unit fashion when appropriate.
As far as support, including Rocky himself, there is a community of contributors that ensure things like CSLA.Net for Xamarin become a reality. There are consultancies that know CSLA and use it on a regular basis depending on the scope of work (and no, not just the consultancy for which I work.)
All things considered, CSLA may not be for you. Like others have indicated, read the site and the books (especially Expert C# 2008 Business Objects.) Ask questions, as the CSLA community tends to give quality advice.
CSLA is described in detail here. The new book is a great starting point. As a great compliment to the book I would recommend checking out our CSLA 3.8 templates. Rocky recommends using a Code Generator, and we have the leading set of templates, that will get you up and running in no time.
Thanks
-Blake Niemyjski (Author of the CodeSmith CSLA Templates)